This invention relates generally, to the treatment of water which passes into the piping of a drainage system by way of a storm drain and relates, more particularly, to filtration systems through which drainwater is routed for purposes of filtering contaminants from the drainwater.
It is known that residue from oil and gasoline spills at service stations, parking lots or similar sites commonly remains at the site of the spill until it is washed away with water by way of a rainfall or a hose-cleaning operation. Of, course, as the residue and/or spilled material is washed to a drain, it is likely to be carried to and mixed with the water supply (e.g. lakes, etc.) from which drinkable water is taken. Similar problems and environmental concerns arise at alternative sites, such as in a leaching pool designed as a detention basin, for filtering, for example, wastewater, stormwater, free-phased organics, petroleum spills, nonpoint source discharge water, vehicle washdown wastewater, wastewater from secondary containment dikes, excavation and construction sites, underground storage tank removals, emergency response conditions, remote wash down areas, and captured water at stream crossings for timber cutting sites.
It is known that treatment systems can be installed within a drainage system for filtering drainwater which enters the drainage system by way of a storm drain so that the water which eventually makes its way through the piping of the drain is filtered of pollutants or other contaminants. However, it would be desirable to provide a drainwater treatment system whose structure and filtration capabilities improves upon those of the drainwater treatment systems of the prior art.
Accordingly, it is an object of the present invention to provide a new and improved drainwater treatment system for installation within a drainage system for filtering contaminants from drainwater flowing therethrough.
Another object of the present invention is to provide such a treatment system which is well-suited for use in a vertical passageway of a drainage system wherein water flows into the vertical passageway through a surface opening of the drainage system.
Still another object of the present invention is to provide such a treatment system which provides a relatively high exposure of drainwater to filter medium as drainwater flows through the treatment system.
Yet another object of the present invention is to provide such a treatment system which permits drainwater to bypass the filter medium during storm flow conditions.
A further object of the present invention is to provide such a system which is uncomplicated in construction and effective in operation.